Mutual coupling between array elements of antenna arrays significantly affect the performances of these arrays in wireless communications applications. The affected performances include signal-to-interference-pulse-noise ratio (SINR) and direction-of-arrival (DOA) estimation in the case of an adaptive array.
Therefore during the design of antenna arrays the problem of mutual coupling is an important consideration. Mutual coupling also adversely determines the dimensions of the arrays in addition to affecting the foregoing performances of the arrays.
Typically, mutual coupling may degrade the radiation patterns for the arrays due to the increase in side lobe levels, the shift of nulls, and the appearance of grating lobes.
Mutual coupling in plate antenna arrays is mainly attributed to space waves, higher-order waves, surface waves, and leaky waves. Generally for conventional plate antenna arrays with a common planar ground conductor, enlarging the spacing between plate array elements, or inter-element spacing, results in reducing or weakening mutual coupling. However, the larger inter-element spacing results in a larger lateral size of the arrays. The larger lateral size of the arrays leads to higher installation cost of wireless communications systems in which such arrays are applied.
There is therefore a need for a laterally compact plate antenna array configured appropriately for reducing mutual coupling between plate array elements.